Auth0 alternatives: A Buying Guide by Situation
Published · Grounded in real discussions
If you're evaluating alternatives to Auth0, you're most likely hitting one of two walls: pricing that stops scaling gracefully as your user base grows, or a feature-complexity mismatch — either Auth0 does too little for your stack, or it does too much in ways that are hard to configure correctly. This guide is organized by your specific situation, not by a generic feature checklist, so you can find the right fit quickly.
Why people leave Auth0 (brief context)
The most common triggers are unpredictable per-user pricing, missing SDKs for non-mainstream frameworks, multi-tenancy complexity that either requires expensive enterprise tiers or significant custom work, and a growing desire to self-host for data sovereignty or EU compliance. If any of those sound familiar, read the section that matches your case.
By situation: which alternative fits
You're building B2B SaaS and need multi-tenancy, RBAC, or enterprise SSO
This is the most crowded segment of the alternatives market, and the options differ significantly on the managed-vs-self-hosted axis.
If you want to stay on a managed service but need something more enterprise-capable — or you're already in an organization that has an Okta relationship — Okta is worth evaluating. It's Auth0's parent company and is frequently cited in the same breath when teams are comparing enterprise identity costs and capabilities. The trade-off is that it's positioned at the same enterprise tier, so it won't solve a pricing problem; it's more relevant if your organization already has procurement leverage there.
If your primary driver is avoiding vendor lock-in and unpredictable pricing, Keycloak is the most-discussed self-hostable option in this segment. It's open-source and gives you full control over deployment, which directly addresses both the cost and the lock-in concern. The honest caveat from user discussions is that it's operationally complex — you're taking on infrastructure ownership in exchange for that control. It's a strong fit for enterprise engineering teams with the DevOps capacity to run it; it's a harder sell for a two-person startup.
FusionAuth is highlighted specifically for teams that need deployment flexibility — the ability to run on-prem, in your own cloud, or managed — without giving up a polished feature set. It earned a dedicated community discussion on its own merits, which is meaningful signal even without a high mention count. If the Auth0 pain is specifically around deployment options rather than raw cost, it's worth a close look.
Ory and Gluu are both listed among open-source identity solutions considered for multi-tenant login at scale. Ory is lower-level and more composable, which means more flexibility but also more integration work. Both are worth evaluating if your team is comfortable building on primitives rather than buying a complete product.
BoxyHQ is a narrower fit: it's open-source and focused specifically on enterprise features like SAML SSO. If your immediate problem is adding SAML SSO to a B2B product without paying Auth0's enterprise tier, it's purpose-built for that. It's not a full Auth0 replacement for teams that need the whole identity stack.
GCP Identity Platform covers multi-tenant login needs but is noted to have gaps — phone number authentication is specifically called out as unsupported under multi-tenancy. That's a concrete disqualifier if your product needs it; otherwise it may be worth evaluating if you're already deep in the GCP ecosystem.
You want open-source or self-hostable auth for data sovereignty or compliance
This is a distinct segment from the B2B SaaS multi-tenancy case above, even though there's overlap. The driver here is typically EU data residency, privacy requirements, or simply wanting to avoid a third-party SaaS holding your user data.
Supabase is the most frequently named option in this space among developers who want integrated auth alongside a database. It's open-source and popular enough to come up in launch discussions for other auth products as the baseline comparison. The appeal is that auth isn't bolted on separately — it's part of a broader backend platform, which reduces integration surface area. If you're starting a new project and want to avoid stitching together multiple vendors, this is worth serious consideration.
Stack Auth is a newer, YC-backed entry that explicitly positions itself as an open-source alternative with both managed and self-hosted deployment options. It's designed to match the developer experience of Auth0 and Clerk while giving you the self-hosting escape hatch. It's newer and has less community track record than Keycloak or Supabase, but if the managed-service DX is important to you and self-hosting is a compliance requirement rather than a preference, it's a credible option to evaluate.
AWS Cognito is a practical choice if your application already runs on AWS and you want auth that stays inside your existing cloud boundary. It's not open-source, but it is cloud-native to AWS and avoids a third-party vendor for teams where that matters. The trade-off is that it's tightly coupled to the AWS ecosystem — it's not a good fit if you're multi-cloud or planning to be.
You're on a non-mainstream framework and Auth0 has no SDK
This is a more targeted pain point. Auth0's SDK coverage leaves developers on stacks like SvelteKit, vanilla Hapi.js, or watchOS without an official integration, forcing manual OAuth implementation.
Clerk is the most-discussed alternative in this segment. It's a managed auth service like Auth0, so it won't solve a self-hosting requirement, but it's actively mentioned by developers on niche or emerging frameworks who are looking for better SDK coverage. If your problem is specifically "Auth0 doesn't have an SDK for my stack," this is the first place to look among managed alternatives.
You're hitting Auth0's SDK internals — hardcoded endpoints, broken OpenID compatibility
This is a narrower, more technical problem: Auth0's client-side SDK hardcodes OAuth token endpoints rather than resolving them dynamically via OpenID Connect discovery, which breaks compatibility when you're integrating with a non-Auth0 identity provider.
Duende is the specific alternative named for this case — it's raised by developers who need proper OpenID configuration-based token endpoint resolution. If your problem is SDK interoperability rather than Auth0's managed service itself, this is the targeted fix rather than a full platform replacement.
How to self-select
- Cost and vendor lock-in are the main drivers, and you have DevOps capacity → Keycloak or FusionAuth for self-hosted control; Ory if you want lower-level composability.
- You need enterprise SSO (SAML) without paying enterprise pricing → BoxyHQ for a focused solution; Keycloak or FusionAuth for a fuller replacement.
- Data sovereignty or EU compliance is the requirement → Supabase if you want integrated auth-plus-database; Stack Auth if you want managed-service DX with a self-hosting option; AWS Cognito if you're AWS-native.
- You're on a niche framework and need better SDK coverage → Clerk is the most-discussed managed alternative for this segment.
- You're integrating with a non-Auth0 identity provider and hitting SDK incompatibility → Duende addresses the OpenID discovery gap specifically.
- You're an enterprise team already in the Okta ecosystem → Okta is the natural comparison, though it won't solve a pricing problem.
No single alternative dominates across all cases — the right choice depends almost entirely on whether your primary constraint is pricing, deployment model, framework support, or enterprise feature access.